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Because of the exoskeleton, arthropods must have flexible areas to be able to move. Such regions are called arthrodial membranes and are particularly vulnerable to bacteria and fungi. Here, we analyzed the secretion in the glands underneath it in a Neotropical harvester (Arachnida, Opiliones) and tested whether it has antiseptical properties. We punctured the membrane, collected and diluted the secretion and quantified proteins and peptides in a spectrophotometer. We also fractionated and analyzed the samples in reversed-phase high-performance liquid chromatography (RP-HPLC) and then incubated the treated fractions and determined growth inhibition by measuring absorbance. The secretions resulted in 42 fractions, among which two had activity against the Gram-positive bacteria Micrococcus luteus and against the yeast Candida albicans. The low concentrations at which the secretions were active are relevant from a biotechnological point of view. For the animals, the secretions possibly prevent infections, including when they are attacked in these regions by predators that pick that spot to bite.

Maternal colonization by Group B Streptococcus during pregnancy increases the risk of neonatal infection due to vertical transmission from mother to fetus before or during labor. The aims of this study were to evaluate the antimicrobial activity of SP80 (obtained from RGE) and its synergism associated with the antibiotic against strains of Streptococcus agalactiae. Biomonitoring of SP80 disclosed antimicrobial activity only in fractions F18, F19, F20 and F42. The broth microdilution was used to determine the antimicrobial activity of SP80 and fractions from SP80 and to establish the MIC of SP80 (2.40 mg/mL). By using the disk diffusion method, fifty-five clinical isolates of S. agalactiae and 1 ATCC were tested against the association of SP80 with antibiotic penicillin G and ampicillin, respectively, for synergistic assessment. The association of SP80 with penicillin G showed that the mean of the inhibition halos decreased, but it was not significant, with p. In contrast, the association of SP80 with ampicillin caused the mean inhibition halos to increase with a p, a significant result. SP80 has antimicrobial activity against S. agalactiae Gram-positive bacteria, and the association with the antibiotic ampicillin showed a synergistic effect, which did not occur when in association with penicillin G.

Lactobacillus acidophilus are Gram-positive bacteria distributed in diverse environments, and as being a component of the normal microbiota of gastrointestinal and urogenital tract, being relevant to humans. Classified as lactic acid bacteria, due to the pro-duction of lactic acid, Lactobacillus can also produce antimicrobial peptides (AMPs), which is a compound synthesized by all forms of life aiming for protecting themselves from threats and to increase their competitivity to survive in a specific environment. AMPs are molecules capable of inhibiting the growth of microorganisms and, due to the indiscriminate use of conventional antibiotics and the emergence of multi-resistant bacteria, they have become an alternative, not only for treating multi-resistant infections, but also for probiotic product confection and food conservation. Considering the rampant rise of resistance, the present study aimed to isolate and characterize antimicrobial peptides from Lactobacillus acidophilus extracts. Samples were obtained from Lactobacillus acid extract supernatant which was pre-fractionated on disposable cartridges, followed by a high-performance liquid chromatography (HPLC). The collected fractions were evaluated in a liquid growth inhibition assay where eight fractions antimicrobial activity were obtained. One of them was selected for further characterization by mass spectrometry (MS), due to its antimicrobial activity against Candida albicans and conclusive results in mass spectrometry analysis. This molecule was identified as a peptide having a molecular mass of 1788.01 Da, peptide sequence NEPTHLLKAFSKAGFQ, and named Doderlin. Interestingly, antimicrobial molecules isolated from L. acidophilus have already been described previously, but few reports in the literature describe an AMP effective against C. albicans as reported here. The results obtained suggest that this newly discovered molecule have a biological property with potential to be applied in pharmaceutical and food companies in the fight against contamination and/or for treating infections caused by microorganisms.IMPORTANCEDoderlin, this newly discovered molecule have a biological property with potential to be applied in pharmaceutical and food companies in the fight against contamination and/or for treating infections caused by microorganisms.